1. Field of the Invention
This invention relates to a cleaning cassette for a tape operatin device such as a video cassette tape deck, and more particularly to a wet-type cleaning cassette which cassette tape deck such as that of the VHS type.
2. Description of the Prior Art
Recently, use of a tape operating device such as a video cassette tape deck has been extensively increased in both the number of times and the amount of time of use of video cassette tapes. With such an increase in use of a video cassette tape deck, concomitantly an increase has occurred in the problem wherein magnetic powder produced by operation of a video cassette tape adheres to a head of the deck and its traveling system, resulting in inconveniences such as turbulence, drop-out, irregular color and color fade-out of an image, upward shifting of a tape due to pollution of a pinch roller, and the like. In view of the foregoing, a cleaning cassette for decontaminating the head and traveling system of the deck has been developed and is commercially available. Such a conventional cleaning cassette is generally classified into a dry-type cleaning cassette which includes a cleaning tape comprising a tape base or body made of polyester and abrasive powder such as silicon coated on or contained in the tape body and a wettype cleaning cassette developed for improving performance of the dry-type cleaning cassette.
The conventional wet-type cleaning cassette is generally constructed in such a manner as shown in FIGS. 1 to 4B. More particularly, the wet-type cleaning cassette includes a cleaning tape 100 comprising a tape body formed by knitting of a suitable fiber material such as polyester or the like and a cleaning liquid such as freon-ethyl alcohol, isopropanol or the like adhered to or impregnated in the tape body and is used for cleaning a revolving head cylinder 102 of a cassette tape deck as shown in FIG. 2. However, in the conventional wet-type cleaning cassette, excessive application of the cleaning liquid to the cleaning tape 100 causes tacky contact between the head cylinder 102 and the cleaning tape 100 to lead to a so-called "sticking phenomenon" which highly increases friction between the head cylinder 102 and the cleaning tape 100, resulting in a failure in a cleaning operation of the cleaning cassette and drawing of the cassette from the deck.
In order to solve such a problem, it is proposed to decrease the contact length or area between the cleaning tape 100 and the head cylinder 102. For this purpose, as shown in FIG. 3, the cleaning cassette is provided with a drawing pin 104 for reducing contact between the tape 100 and the head cylinder 102, so that introduction of the tape into the deck is varied in such a manner that it is passed in the form of a substantially V-shape with respect to the head cylinder 102 when the cassette is loaded in the deck, resulting in decreasing a contact area or length between the head cylinder 102 and the cleaning tape 100 to reduce the sticking phenomenon.
Unfortunately, such an approach causes both sides of the head cylinder 102 to be pressedly contacted with the cleaning tape 100 irrespective of decreasing the contact area therebetween, as shown in FIG. 3, resulting in an increase in friction therebetween This is enhanced depending on the cleaning liquid used. Also, the approach has another disadvantage of leading to an increase in load to the head cylinder to a degree sufficient to render use of the cleaning cassette for a cassette deck which exhibits driving force of a low level substantially impossible.
In addition, use of the drawing pin 104 causes the cassette to fail in accommodating to pushing of the cleaning tape by the deck, resulting in an increase in frictional resistance occurring during traveling or running of the cleaning tape during a cleaning operation. Thus, the cleaning tape fails to uniformly carry out a cleaning operation. Also, this causes overloading in a tape deck of which driving force is low, thereby leading to damage of the deck, so that reliability of the cleaning cassette in the operation deteriorates. Further, this causes a further disadvantage of not only rendering assembling of the cleaning cassette very difficult because mounting of a tape-contact reducing device including the drawing pin 104 on a casing 108 of the cleaning cassette is highly troublesome but complicating the structure of the cassette.
Furthermore, in general, the video cassette tape deck is adapted to carry out recording and/or reproducing according to a helical scan system using a revolving head, so that it is required to obliquely arrange the head cylinder 102 as shown in FIGS. 4A and 4B. Accordingly, in the conventional cleaning cassette in which the cleaning tape 100 is passed in the form of a V-shape in the deck, it is required to obliquely arrange the drawing pin 104 together with tilting pins 106. However, such an approach is not necessarily applied to all kinds of video cassette tape decks because the angle of inclination of the head cylinder 102 is varied depending on a type of the video tape deck. More particularly, this causes damage of an edge of the cleaning tape 100 represented by fraying of the edge depending on the video tape deck. It was found that the damage mainly results from non-uniform application of tension to the cleaning tape 100 due to a difference between the inclination angle of the head cylinder 102 and the angle of arrangement of the drawing pin 104. An increase in a difference between both angles leads to upward shifting of the cleaning tape, resulting in the tape being often entangled.
Reference numerals 110 and 112 designate a feed reel and a take-up reel, respectively.
Accordingly, it would be highly desirable to develop a cleaning cassette which is capable of accomplishing a stable and smooth cleaning operation while preventing damage of a cleaning tape.